Clutch mechanism for a sewing machine drive



Dec. 9, 1958 F. w. LANGE Em 2,863,410

CLUTCH MECHANISM FOR A SEWING MACHINE DRIVE Filed Feb. 3, 1955 2 Sheets-Sheet 1 Dec. 9, 1958 F. W. LANGE ETAL CLUTCH MECHANISM FOR A SEWING MACHINE DRIVE Filed Feb. 5, 1955 2 Sheets-Sheet 2 6' 5 k 3 3 u 21 Q a 19 fvze United States Patent() CLUTCH MECHANISM FOR A SEWING MACHINE DRIVE Application February 3, 1955, SerialNo. 485,859

3 Claims. (Cl. 112-220) This invention relates to, a clutch. apparatus .for operably connecting and disconnecting a drive element to a driven element.

, Theinvention is particularly but not exclusively applicable: to a sewing. machine. In thev ordinary sewing machine there. is provided a drive shaft for operating the working parts of the machine. Thus, the drive shaft which is usually driven by a motor or other driving means serves to=operate the needle drive, the shuttle, the cloth feed apparatus,.the thread take-uplever and other operating parts. In order to rotate the drive shaft, there is customarily provided a drive wheel thereon with the motor or similar means driving through this wheel. The wheel is alsoordinarily used. for operating the bobbin winding mechanism of the machine for winding the bobbin with thread.

In order to prevent rotation of the drive shaft and thus operation of the parts of the sewing machine when the bobbin is being wound, it is customary to provide a clutch mechanism for releasablysecuring the drive wheel to the drive shaft. Then when the sewing machine is operating in its normal manner, the clutch mechanism serves to bind the wheel to the shaft. When the wheel is rotated to. wind the bobbin or for other non-sewing purposes, the clutch can be released: so that the drive wheel will. rotate freely on the shaft and without rotating the shaft. The invention here is concerned primarily with an improved releasable clutch apparatus and asso ciated parts of the sewing machine.

The improved clutch apparatuswof' this invention comprises. a clutch member operably attached. to the shaft for rotation therewith, a clutch i member operably attached to the drive. wheel for rotation therewith, the

clutch members including cooperating locking portions for releasably attaching together the clutch member-sand thus the shaft and wheel for'rotation as a unit, and means for thusly releasably engaging the clutch members.

The invention will be described as illustrated in the embodiment shown in the drawings. Of the drawings:

Fig. 1 is a fragmentary end elevational view partially in section of a sewing machine head embodying the invention.

Fig. 2 is a sectional elevational view showing the drive wheel, drive shaft, releasable clutch apparatus and associated. parts of the sewing machine.

Fig. 3 is a fragmentary sectional elevation, taken substantially along line 3-3 of. Fig. 2.

Fig.v 4 is a fragmentary sectional elevation, taken sub stantially along line 44 of'Fig. 2.

Fig; 5 is a fragmentary sectional elevation, taken substantially along line 5-5 of Fig. 2.

Fig. 6 is a side elevatioual view showing the operating face of one of the clutch members forming a part of the improved clutch apparatus.

Fig. 7 is an enlarged-fragmentary sectional view showing the clutch members in separated arrangement.

'ii atented Dec. 9, 1958 Fig. 8 is a fragmentary sectional view, taken substantially along line 8-45 of Fig.2.

Fig. 9 is a fragmentary side elevational view of, the clutch members in cooperating contact with each. other.

The sewing machine head illustrated in the accom: panying drawings isof the ordinary household type and preferably employs the driving arrangement illustrated in the copcnding application of Frank S. Howard,,Ser,ial No. 288,253, filed May 16, 1952. The. sewing machine head comprises a frame 10 having a substantially hori zontal drive shaft 11in the upper portion thereof and drive wheel 12 mounted on the shaft 11L The wheel 12 is rotated by a rubber driving spindle 13 hearing against an inner surface portion 12a. of the. wheel. The spindle 13 is mounted on a motor shaft 14" which forms a part of and is rotated by an electric'motor 15. Means such. as a spring (not shown) isprovided urging the motor and thus the spindle. 13 outwardly against the surface portion 12a of the drive wheel 12.. lnithe-normal sewing operations, rotation of the spindle 13 rotates the wheel l2v which. in turn rotates the drive shaft. 11 and operates the parts of the sewingmachinei In the embodiment shown, the motor 15 rotates thewheel lz in a counterclockwise direction as viewed from the righthand end of Figs. 1 and 2. i

The end of the. drive shaft 11. is. provided with an elongatedcylindricalbearing member 16; fastened to. the shaft. This endof theshaft is hollow. toprovide a hollow chamber Ella and this hollow end is split into a plurality of branches 1111 which: are internally taper threaded; The tapered threaded internal surface portions of these branches 11b taper inwardly and toward: each other, as illustrated in Fig. 2. Thereis also provided a headless taper screw 17 which engagesthe threads onthe. branches 11b to exert a great. expanding force thereon. This screw is screwed inwardlyvtoforce the shaft branches 11b outwardly and bind them tightly against the bearing member ie so that the bearing, member and. the shaft 11 are connected for rotation as a unit.

The inner end of the bearing member 16 is provided with anoutwardly extending annular flange 16o. The drive wheel 12 is provided. with. an enlarged. essentially annular innen portion 12!) which. ismounte'd on the bearing member 16. The inner end of this enlarged portion i211 is provided. with a. hollow chamber 110 which surrounds the flange 16a.

The wheel: IiZis. slidable longitudinally on the bearing member in. This slidingmovement is provided in order to' selectively lock and release the wheel. on the bearing member 16 and thus on theshaftll- In order tosecure a positive lock, the wheelbase or inner portion 12b and thebearing memberdlfi are provided with interlocking clutch members having locking portions which cooperate. to attachtogether the shaft and the wheel for rotation as a. unit when desired. In the; embodiment shown, the clutch apparatus includes a first clutch member 18 mounted on the flange 16a and facing the drive wheel 12 and a second, clutch. member 19rm-ounted on the wheel, 12 and facingthe flange 16a. Both clutch members are .locatedwithinl the space provided by the hollow chamber 11c and are positioned between the flange 16a. and the. adjacent surface portion li-Zq of the wheel 12.

The first clutch member 18 is in. the form ofan annular ring that may be fastened to the flange 1611 by means of aplurality of rearwardly extending. studs 2t engaging similarly shaped openings 16b in the. flange 16a. The second clutch member 19 may be similarly fastened to the wheel 12b by studs 21 engaging similar openings in the wheel... The clutch members 18 3111(1119 may also bemade integral with their respective. parts of the. ap-

paratus. Each clutch member 18 and 19 is provided with a series of cooperating locking portions. In the embodiment shown, these locking portions comprise a series of shallow projecting detents 18a and 1911, as illustrated most clearly in Figs. 6 and 7. These detents have upper inclined surfaces of relatively large area, all inclined in the same direction around the axis, with the maximum height of each detent being relatively small so that the slope of each detent upper surface is relatively shallow. With this construction when the wheel 12 has been moved inwardly to its greatest extent as illustrated in Fig. 2, the detents 18a and 19a engage each other as they are arranged to internest,-thereby locking securely the wheel 12 to' the bearing member 16 and thus to the drive shaft 11 for rotation as a unit. When the wheel has been moved outwardly a distance sufficient to disengage the detents 18a and 19a as illustrated in Fig. 7, the wheel 12 is then free to rotate on the bearing member 16. Thus, in the illustrated embodiment, the maximum height of each detent 18a and 19a is less than a normal minimum axial movement of the wheel 12 along the bearing member 16.

The detents 18a and 19a in the embodiment shown are helical cam-lobes that have engaging cam surfaces 18a and 19a mating and operating to urge the cam members 18 and 19 away from each other by a wedging action as illustrated by the lines of force indicated at 18b and 19b.

In order to move the wheel 12 longitudinally on the bearing member 16 to engage and disengage the detents 18a and 19a, the outer end of the bearing member 16 which extends beyond the outer end of the shaft 11 is internally threaded as indicated at 160. There is then provided a rotatable knob 22 having an inwardly projecting shank 22a similarly threaded and engaging the threads 160. This knob 22 when rotated moves inwardly and outwardly relative to the shaft 11 and moves the drive wheel 12 along the bearing member 16. i

In order to provide low friction surfaces, there is provided a first bearing member 23 having a low coefficient of friction. This first bearing member is attached to the outer annular surface of the wheel 12 that surrounds the outer end of the bearing member-16. The bearing member 23 is attached to the wheel by a plurality of studs 24 engaging similar openings in the wheel 12.

There is also provided a second bearing member 25 hearing against the outer surface of the first bearing member'23, as illustrated in Fig. 2. This second bearing member 25 is provided with diametrically located inwardly extending ears 25a engaging similarly shaped slots 16d on the outer end of the bearing member 16. The second bearing member 25 is also provided with three outwardly extending projections 25b spaced substantially 120 apart around the outer periphery thereof. The knob 22 is provided with a stop bolt 26 extending through the knob and having a projecting shank portion 261: located adjacent to the outer edge of the bearing member 25 and between two adjacent projections 25b. This shank portion 26a engaging the pair of adjacent projections 25b determines the extent of rotational movement of the knob 22.

When the knob 22 is rotated slightly less than 120 or from its position against one bearing member projection 25b to the, next bearing member projection 25b, the knob is moved inwardly or outwardly relative to the bearing member 16 and thus the shaft 11. This movement is caused by the threaded engagement of the knob shank 22a with the bearing member 16. These threads have a pitch such that they cause movement of the wheel 12 a sufficient distance to release the detents 18a and 19a as shown in Fig. 7 when the knob is rotated in a counterclockwise direction, as viewed from the right-hand end of the embodiment shown in Figs. 1 and 2. Then, when the knob is turned in a clockwise direction, the wheel 12 is moved to the left, as viewed in Figs. 1 and 2,

to engage thedetents and lock the wheel on the bearing member 16 and thus on the shaft 11.

The three projections 25b are provided so that the proper relationship can be obtained for moving the wheel so as to engage and disengage the detents on rotation of the knob. Thus in the embodiment shown, the second bearing member 25 has four possible positions relative to the bearing member 16. It has the position shown in Fig. 3, the position where it is removed from engagement with the end of the bearing member and rotated and then placed back in engagement with the hearing member 16, and the reverse of these two positions when the bearing member is turned over. With this variation and with providing three projections, it is simple to assemble thesecond bearing member 25 on the machine so that rotation of the knob 22 to move the shank portion 26a of the bolt 26 from engagement with one projection 25b to engagement with the next projection 25b will cause the detents to engage or disengage, depending upon the direction of this movement.

When the operating parts of the clutch apparatus are in the positions shown in Figs. 1 and 2, the detents 18a and 1911 are in engagement so that rotation of the drive wheel 12 by means of the motor 15 and spindle 13 will cause rotation of the drive shaft 11. When it is desired to disengage the clutch apparatus, the knob 22 is rotated in a counterclockwise direction as viewed from the outer end of this knob. The extent of this rotation of the knob is determined by the shank portion 26a contacting the next bearing projection 25b. The extent of this movement is sufficient to withdraw the knob 22 from the bear ing member 16 so that the Wheel 12 can move away from the flange 16a. This outward movement of the wheel is caused by the spindle 13 always urging the wheel outwardly. The extent of movement is suflicient to disengage the detents 18a and 19a. The wheel may then be rotated freely on the bearing 16 without rotating the drive shaft 11.

Because the motor 15 and spindle 13 urge the wheel 12 outwardly, the bearings 23 and 25 are provided so as to avoid excessive wear and heating of the wheel rotating against the stationary knob 22. These bearings are made of a low friction material such as molded nylon.

Having described our invention as related to the embodiment shown in the accompanying drawings, it is our intention that the invention be not limited by any of the details of description, unless otherwise specified, but

rather be construed broadly within its spirit and scope as,

set out in the accompanying claims.

We claim:

1. In a sewing machine, apparatus comprising: a drive shaft rotatable about its axis; an elongated bearing mem' ber on said shaft for rotation therewith having an annular flange on its inner end; a drive wheel rotatable on said bearing member and slidable axially thereon; a first clutch member attached to said flange; a second clutch member attached to said wheel, the clutch members including cooperating engageable locking portions of shallow depth for releasably attaching together said clutch members; a knob threaded to said shaft positioned on the side thereof opposite to said flange, the knob selectively moving said wheel toward and away from said flange on rotation of the knob to engage and disengage said clutch members; an annular first bearing concentric to said shaft adjacent to the outer side of said wheel and attached thereto; an annular second bearing concentric to said shaft between said first bearing and said knob and attached to said bearing member, said second bearing having spaced stop means thereon; and means on said knob engaging said stop means for limiting the extent of said rotation of said knob.

2.. In a sewing machine, apparatus comprising: a drive shaft rotatable about its axis; an elongated bearing memher on said shaft for rotation therewith having an annular flange on its inner end; a drive wheel rotatable on said bearing member and slidable axially thereon; a first clutch member attached to said flange; a second clutch member attached to said wheel, the clutch members including cooperative engageable locking portions of shallow depth for releasably attaching together said clutch members; a knob threaded to said shaft positioned on the side thereof opposite to said flange, the knob selectively moving said wheel toward and away from said flange on rotation of the knob to engage and disengage said clutch members; an annular first bearing concentric to said shaft adjacent to the outer side of said wheel and attached thereto; an annular second bearing concentric to said shaft between said first bearing and said knob and attached to said bearing member, said second bearing having spaced stop means thereon; means for positioning said first and second bearings at any of a plurality of positions relative to each other; and means on said knob engaging said stop means for limiting the extent of said rotation of said knob.

3. In a sewing machine, apparatus comprising: a drive shaft rotatable about its axis; an elongated bearing member on said shaft for rotation therewith having an annular flange on its inner end; a drive wheel rotatable on said bearing member and slidable axially thereon; a first clutch member attached to said flange; a second clutch member attached to said wheel, the clutch members including cooperating engageable locking portions of shallow depth for releasably attaching together said clutch members; a knob threaded to said shaft positioned on the side thereof opposite to said flange, the knob selectively moving said wheel toward and away from said flange on rotation of the knob to engage and disengage said clutch members; a first bearing attached to said drive wheel; a second bearing attached to said bearing member and normally outwardly of and engaging said first bear ing; and means including cooperating projections on said second bearing and said knob to limit the extent of movement thereof away from said flange to that sufficient only to disengage said locking portions.

References Cited in the file of this patent UNITED STATES PATENTS 1,913,046 Callan June 6, 1933 2,247,381 Hohmann July 1, 1941 2,398,570 Wildhaber Apr. 16, 1946 FOREIGN PATENTS 466,880 Italy Nov. 20, 1951 

